检索结果-南通市图书馆

Effect of Organic Ligands on Biological Availability of Inorganic Phosphorus in Soils

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Pedosphere 2004年第1期14卷 85-92页

作者： FENGKe LUHai-Ming SHENGHai-Jun WANGXiao-Li MAOJian agriculturalcollege YangzhouUniversityYangzhou225009（China）

Citrate, oxalate, tartrate and malate were added into soils during the growthperiod of ryegrass to study the effect of different organic ligands on the release of variousinorganic P (Pi) fractions in a yellow-brown soil and a paddy soil. The results showed that oxalatewas most effective in promoting the release of total Pi in the yellow-brown soil and tartrate in thepaddy soil. The dominant Pi fractions released from the yellow-brown soil were calcium phosphate(Ca-P) and aluminum phosphate (Al-P) and those from the paddy soil were iron phosphate (Fe-P) andreductant soluble phosphate (O-P) mobilized by tartrate. Phosphorous-mobilizing capability oforganic acids in the yellow-brown soil revealed the following order: oxalate > citrate > malate >tartrate. In the paddy soil, the order was tartrate > citrate ≈ oxalate > malate. It wasdemonstrated that organic ligands were different in their capabilities of mobilizing Pi and the sameorganic ligand showed also a discrepancy in mobilizing P in different soils. Although the additionof organic ligands into soils could increase the amount of P taken up by ryegrass, the more uptakeof P, however, was not only due to the more release of Pi, but also partly from organic P. In manycases, organic ligands promoted the release of the total Pi, while different fractions showeddifferent trends: some increased and others decreased.

关键词： biological availability inorganic P release organic ligands ryegrass

Effect of Ammonium Fixation on Determination of N Mineralized from Soil Microbial Biomass

在线全文

学校读者我要写书评

暂无评论

Pedosphere 1997年第2期7卷 127-132页

作者： YINSHIXUE LIANGYONGCHAO 等 DepartmentofAgronomy AgriculturalCollegeYangzhouUniversityYangzhou225009（China） CollegeofNaturalRes

Two soils with relatively high (Soil 1) and low (Soil 2) ammonium fixation capacities were used in thisstudy to extalne the effect of ammonium fixation on the determination of N mineralised from soil ndcrobialbiomass. organism suspellsioll was quantitatively introduced to Soil 1 at various rates. Both fumigation-incubation (FI) and fumigation-ext raction (FE ) met hods were used to t reat t he soil. The amount of ffeedNH4+-N increased with increasing rate of organism-N addition. A close correlation was found between theamoun of fixed aznmonium and the rate of organism-N addition. The net increso of fixed NH4+-N wereequivalent to 38% and 12% of the added organism-N for FI and FE treatments, respectively in this specificsoil. To provide isotopic evidence, 15N-labelled organism-N was added to Soils 1 and 2 at 121.4 mg N *** FI treatment, 22 and 3 mg N kg-1 of labelled N were found in the fraction of fixed NH4+-N in Soils 1 and2 respectively; while in FE treatment, 9 mg N kg-1 of labelled N was found in the fraction of fixed NH4+-Nin Soil 1 only. There was no labelled N in the fraction of fixed NH4+-N in Soil 2. In all of the unfumigated(check) soils, there was little or no labelled N in the fixed fractions, probably because the organism-N addedwas easily mineralized and nitrified. A mean of 0.64 for KN value, the fraction of N ndneralized in the killedmicrobial biomass, was obtained with inclusion of the net increase of fixed NH4+-N. The corresponding valuecalculated with exclusion of the net increase of fixed NH4+-N was 0.46. It was concluded that ammniumfixation was a problem in determination of KN, particularly for soils with a high ammonium fixation *** also showed that microbial biomass N measurement by FE method was less affected by ammoniumprocess than that by FI method.

关键词： ammonium fixation fumigated soil microbial biomass N

Reduction of Nitrate to Ammonium in Selected Paddy Soils of China *1

在线全文

学校读者我要写书评

暂无评论

Pedosphere 1998年第3期8卷 221-228页

作者： YINSHIXUE SHENQIRONG 等 DepartmentofAgronomy AgriculturalCollegeYangzhouUniversityYangzhou225009（China） CollegeofResourcesa

Three paddy soils were examined for their capacities of dissimilatory reduction of nitrate to ammonium (DRNA). 15 N labelled KNO 3 was added at the rate of 100 mg N kg -1 . Either glucose or rice straw powder was incorporated at the rate of 1.0 or 2.0 mg C kg -1 respectively. Three treatments were designed to keep the soil saturated with water: A) a 2 cm water layer on soil surface (with beaker mouth open); B) a 2 cm water layer and a 1 cm liquid paraffin layer (with beaker mouth open); and C) water saturated under O 2 free Ar atmosphere. The soils were incubated at 28 oC for 5 days. There was almost no 15 N labelled NH + 4 N detected in Treatment A. However, there was 1.4 to 3.4 mg N kg -1 15 N labelled NH + 4 N in Treatment B and 2.1 to 13.8 mg N kg -1 in Treatment C. Glucose was more effective than straw powder in ammonium production. Because there was sufficient amount of non labelled NH + 4 N in the original soils, 15 N labelled NH + 4 N produced as such should be the result of dissimilatory reduction. Studies on microbial population showed that there were plenty of bacteria responsible for DRNA process (DRNA bacteria) in the soils examined, indicating that number of DRNA bacteria was not a limiting factor for ammonium production. However, DRNA bacteria were inferior in number to denitrifiers. DRNA process in soil suspension seemed to start after 5 days of incubation. Glycerol and sodium succinate, though both are readily available carbon sources to organisms,did not facilitate DRNA process. DRNA occurred only when glucose was available and at the C/NO 3 - N ratio of over 12. It seemed that both availability and quality of the carbon sources affected DRNA.

关键词： carbon source dissimilatory reduction of nitrate to ammonium microbial population

Preferential Fixation of Ammonium to Potassium by Soils

在线全文

学校读者我要写书评

暂无评论

Pedosphere 1996年第1期6卷 35-38页

作者： TNAGYAN FENGKE 等 DepartmentofAgronomy AgriculturalCollegeYangzhouUniversityYangzhou225009China DepartmentofAgronomy

Ten soils collected from different parts of China were used in a series of experiments to study fixation of NH￣+_4 and K￣+ by soils. When K￣+ was added concurrently with or prior to NH￣+_4, the soils were found to fix more moles of NH￣+_4 than those of K￣+, irrespective of the mole ratios of NH￣+_4 to K￣+ that were added.

关键词： ammonium fixation potassium fixation soils

Denitrification and Nitrate Reduction to Ammoniumin Taihu Lake and Yellow Sea Inter-Tidal MarineSediments

在线全文

学校读者我要写书评

暂无评论

Pedosphere 1999年第4期9卷 305-309页

作者： YINSHIXUE SHENQIRONG 等 AgronomyDepartment AgriculturalCollegeYangzhouUnivesityYangzhou225009China CollegeofResourcesandEn

Denitrification and nitrate reduction to ammonium in Taihu Lake and Yellow Sea inter-tidal marinesediments were studied. The sediment samples were made into slurry containing 150 g dry matter per *** amounts of glucose and 5 mmol L-1 of potassium nitrate were added in order to achieve differentratios of glucose-C to nitrate-N. Acetylene inhibition technique was applied to measure denitrification in theslumes. All samples were incubated anaerobically under argon atmosphere. Data showed that Taihu Lakesediment produced more N2O than marine sediment. Denitrification potential was higher in Taihu Lakesediment than in marne one. Glucose added increased denitrification activity but not the denitrification po-tential of the sediments. Dissimilatory nitrate reduction to ammonium seemed to occur in marine sediment,but not in freshwater one. When the marine sediment was treated with 25 mmol L-1 glucose, its denitrification poteatial, as indicated by maximum N2O production by acetylene blockage, was lower than that treatedwith no or 2.5 mmol L-l glucose. Acetylene was suspected to have inhibitory effect on dissimilatory nitratereduction to ammonium.

关键词： denitrification dissimilatory nitrate reduction to ammonium marine sediment Taihu Lakesediment

Abundance and biomass of meiobenthos in the spawning ground of anchovy (Engraulis japanicus) in the southern Huanghai Sea

在线全文

学校读者我要写书评

暂无评论

Acta Oceanologica Sinica 2005年第3期24卷 94-104页

作者： LIUXiaoshou ZHANGZhinan HUANGYong CollegeofMarineLifeSciences OceanUniversityofChinaQingdao266003China CollegeofMarineLifeSciences OceanUniversityofChinaQingdao266003China／／AgriculturalCollegeLiaochengUniversityLiaocheng232000China

A grid of 22 stations, giving a broad coverage of the spawning ground of anchovy in the southern Huanghai Sea was selected. Undis- turbed sediments were taken from sampling stations during the cruise in June 2003. The average abundance of meiofauna is (1 584± 686) ind./10cm2, with corresponding biomass (dwt) of (1 086±425)!μg/10cm2. The pattern of abundance of meiofauna is similar to the pattern of biomass. There are 65.88% meiofauna in 0￣2 cm sediments, 27.66% in 2￣5 cm sediments and 6.47% in 5￣8 cm sediments. The Spearman correlation analysis between meiofauna and environmental factors shows that abundance of meiofauna, free living ma- rine nematodes, benthic copepods has significant positive correlations with Chl-a. And the abundance of copepods has significant posi- tive correlations with several factors such as Chl-a, Pha-a, Chl-a plus Pha-a and organic matter. A total of 18 meiofauna groups are i- dentified. Nematode is the most dominant group, average abundance (1 404±670) ind/10cm2, accounting for 88.65%, and the follow- ing groups are also important: benthic copepods (5.48%), kinorhyncha (1.26%), polychaeta (1.07%). By biomass, dominant groups are nematodes (51.72%), polychaeta (21.84%), copepods (14.87%), ostracoda (4.92%), kinorhyncha (3.67%). A total of 90 species of ne- matodes are identified. The species composition of nematodes is listed based on selected two stations 7794 (coastal area) and 10694 (cold water mass in deep waters).

关键词： meiofauna free living marine nematodes benthic copepods abundance biomass southern Huanghai Sea

Effects of Atmospheric CO_2 Enrichment, Applied Nitrogen and Soil Moisture on Dry Matter Accumulation and Nitrogen Uptake in Spring Wheat

在线全文

学校读者我要写书评

暂无评论

Pedosphere 2002年第3期12卷 207-218页

作者： LIFUSHENG KANGSHAOZHONG agriculturalcollege GuangxiUniversityNanning530005（China） EeyLaboratoryofAgriculturalSoil＆WaterEngineeringintheAridandSemiaridAreas MinistryofEducationNorthwestSci－TecUniversity

Spring wheat (Triticum aestivum L. cv. Dingxi No. 8654) was treated with twoconcentrations of atmospheric CO_2 (350 and 700 μmol mol^(-1)), two levels of soil moisture(well-watered and drought) and five rates of nitrogen fertilizer (0, 50, 100, 150, and 200 mgkg^(-1) soil) to study the atmospheric CO_2 concentration effect on dry matter accumulation and Nuptake of spring wheat. The effects of CO_2 enrichment on the shoot and total mass depended largelyon soil nitrogen level, and the shoot and total mass increased significantly in the moderate to highN treatments but did not increase significantly in the low N treatment. Enriched CO_2 concentrationdid not increase more shoot and total mass in the drought treatment than in the well-wateredtreatment. Thus, elevated CO_2 did not ameliorate the depressive effects of drought and nitrogenstress. In addition, root mass decreased slightly and root/shoot ratio decreased significantly dueto CO_2 enrichment in no N treatment under well-watered condition. Enriched CO_2 decreased shoot Ncontent and shoot and total N uptake; but it reduced root N content and uptake slightly. Shootcritical N concentration was lower for spring wheat grown at 700 μmol mol^(-1) CO_2 than at 350μmol mol^(-1) CO_2 in both well-watered and drought treatments. The critical N concentrations were16 and 19 g kg^(-1) for the well-watered treatment and drought treatment at elevated CO_2 and 21 and26 g kg^(-1) at ambient CO_2, respectively. The reductions in the movement of nutrients to theplant roots through mass flow due to the enhancement in WUE (water use efficiency) and the increasein N use efficiency at elevated CO_2 could elucidate the reduction of shoot and root Nconcentrations.

关键词： CO_2 enrichment critical N concentration dry matter nitrogen uptake soilmoisture

Effects of Four Pesticides on Grain Growth Parameters of Rice

在线全文

学校读者我要写书评

暂无评论

Agricultural Sciences in China 2004年第5期3卷 364-370页

作者： WUJin-cai DONGBo LIDong-hu QIUHui-min YANGGuo-qing DepartmentofPlantProtection AgriculturalCollegeYangzhouUniversityYangzhou225009P.R.China

Effect of four commonly used pesticides, triadlmefon, jingganmycin, triazoplos andimidacloprid, on grain growth parameters was examined using a growth equation in thepresent paper. Two hundreds of spikes, not damaged by pests were simultaneously markedper plot during the heading stage of rice. Rice plants were sprayed at 1 d after ***, 20 spikes were sampled at 4 d intervals and dried in an oven. Then, 10superior and inferior grains were picked from each spike, and brown rice was weighedafter shelling, respectively. First, second and third order derivates were deduced fromthe following grain growth formula:bt-aKwe1+=, where W was the weight of 100 grains brownrice at time t; K was maximum of grain growth; a and b were parameters of the formula. Theparameters were calculated as following:Where R0, △t, GT and Vmax were initial growth power, active growth stage, accumulativeweight of dried content during △t and maximum growth rate, respectively. The resultshowed that GT and K of superior grain following 22.5 and 45 ***-1 of imidaclopridsprays were significantly reduced, and △t was significantly decreased for 112.5 and ***-1 jingganmycin treatments. In addition, the high dose of imidacloprid signifi-cantly reduced the weight of 1000 rice grains by 9.77%. However, there was no significantdifference for the weight of 1000 grains between the high dose of jingganmycin and thecontrol, indicating that effective duration of jingganmycin on grain filling was shorterthan that of imidacloprid.

关键词： Pesticides Rice Grain growth Parameters Effect

Factors Affecting Agrobacterium-Mediated Transformation Efficiency in Rice

在线全文

学校读者我要写书评

暂无评论

Rice science 2004年第4期11卷 181-185页

作者： CHENEn-hui ZHANGPing ZUOShi-min LIAi-hong ZHANGYa-fang CHENZong-xiang PANXue-biao agriculturalcollege YangzhouUniversityYangzhou225009China agriculturalcollege YangzhouUniversity.Yangzhou225009.China／／LixiaheAreaAcademyofAgriculturalSciencesofJiangsuProvinceYangzhou225002China

Several important factors affecting the efficiency of Agrobacterium-mediated rice transformation were studied with several predominant commercial indica and japonica rice cultivars. As far as indica rice callus was concerned, CC medium was the best and the quality of callus was improved with the addition of 1.0 to 2.0 mg/L ABA. It decreased the percentage of browning calli and improved the callus growing state by addition of a certain amount of sorbitol to the subculture medium. NB medium was the best for callus initiation of japonica rice, but the improvement in the quality of callus of japonica subspecies was not obvious by adding ABA. During the period of subculture, to a certain degree, increasing the sucrose concentration could improve the proportion of hygromycin resistant calli. Furthermore, the transformation efficiency would be higher by applying selection pressure in the selection stage, removing selection pressure during the plantlet differentiation period and applying selection pressure again during seedling hardening period. Besides, suitable combination of plant hormones was beneficial for callus differentiation. An efficient /Agrobacterium-mediated rice transformation system had been established for several rice cultivars and a lot of transgenic rice plants had been obtained.

关键词： rice Agrobacterium callus hormones transformation